Modifying substrates by coating the surfaces thereof in such a manner that the surface will have certain functional properties is known. For example, tellurium-containing films can be used in the formation of GST films (germanium-antimony-tellurium films, “GST” usually refers to Ge2Sb2Te5, but may include other compositions such as GeSbTe2) for the application of PRAM (Phase Change Random Access Memory). Furthermore, tellurium is used in combination with other metals for PRAM fabrication, such as InGe2Te2, AsSbTe, CrSbTe or MoSbTe.
The main industrial options to enable the deposition of such films with reasonable throughput and acceptable purity are deposition techniques, such as MOCVD (Metal-Organic Chemical Vapor Deposition) or ALD (Atomic Layer Deposition). Metal-organic or metal-halide precursors are required for those processes. The requirements for a metal-organic compound to be suitable for an industrial process include:                being liquid at room temperature or having a low melting point for distribution considerations        volatility; and        thermal stability.        
Various tellurium metal-organic compounds have been considered as precursors to enable such deposition. Examples include:                Imines such as (tBuNTeNtBu)2 and (tBuNTe)3 have been reported by Chivers et al. (J. Am. Chem. Soc. 1995, 117, 2359); however, these precursors exist as dimers and trimers, acting to decrease the volatility of the molecule,        Amines such as Te(N(SiMe3)2)2 have been reported by Björgvinsson et al. (Inorg. Chem. 1990, 29, 5140); however, this precursor exhibits dimerism in the solid state, resulting in a decreased volatility over a monomer species.        Diorganyl tellurides are also known in the literature (M. Renson, ‘The Chemistry of Organic Selenium and Tellurium Compounds’, Wiley, New York, 1986, Vol. 1, p. 399).        Atomic layer deposition of GST films has been achieved by Choi et al. (Chem. Mater. 2007, 19 4387-4389) using the alkyl precursor Te(iPr)2. Alkyl precursors have the benefit of higher volatility; however, the low decomposition temperature of Te(iPr)2 (˜200° C.) compared with the Sb and Ge precursor lead to a CVD-type behavior.        Tellurium alkoxide precursors are known; however, they have significantly lower volatilities than alkyl precursors.        Diorganyltellurium dihalides are known, however they exist as crystalline solids with low volatility (K. J. Irgolic, ‘The Organic Chemistry of Tellurium’, Gordon & Breach, New York, 1974). In addition, the potential for halogen contamination of the film presents halogen containing precursors as unattractive for the deposition process.        
Thus, a need remains for suitable tellurium metal-organic compounds that enable the deposition of tellurium-containing films.
The tellurium metal-organic compounds must present the features of 1) being liquid or having a melting point below 80° C., 2) being volatile enough for use industrial ALD and/or MOCVD tools, and 3) enabling the deposition by MOCVD and ALD of metal containing films such as InxGeyTe, M1xSbyTez, SbxTey or CdTe, with M1 being selected from but not limited to germanium, chromium, or arsenic.